diff --git a/.github/workflows/electron.yml b/.github/workflows/electron.yml
index a2c125e1b..a781f84af 100644
--- a/.github/workflows/electron.yml
+++ b/.github/workflows/electron.yml
@@ -468,6 +468,13 @@ jobs:
 
           security find-identity -v -p codesigning $KEYCHAIN_PATH
 
+          if ! security find-identity -v -p codesigning $KEYCHAIN_PATH | grep -q "3rd Party Mac Developer Installer"; then
+            echo "No '3rd Party Mac Developer Installer' identity found in the keychain."
+            echo "electron-builder needs this to wrap the signed .app into a .pkg for MAS."
+            echo "Check that MAC_INSTALLER_CERTIFICATE_BASE64 holds a valid, non-expired installer cert."
+            exit 1
+          fi
+
       - name: Build macOS App Store Package
         if: steps.check_certs.outputs.has_certs == 'true'
         env:
@@ -1066,6 +1073,13 @@ jobs:
 
           security find-identity -v -p codesigning $KEYCHAIN_PATH
 
+          if ! security find-identity -v -p codesigning $KEYCHAIN_PATH | grep -q "3rd Party Mac Developer Installer"; then
+            echo "No '3rd Party Mac Developer Installer' identity found in the keychain."
+            echo "electron-builder needs this to wrap the signed .app into a .pkg for MAS."
+            echo "Check that MAC_INSTALLER_CERTIFICATE_BASE64 holds a valid, non-expired installer cert."
+            exit 1
+          fi
+
       - name: Check for App Store Connect API credentials
         id: check_asc_creds
         run: |